<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>

   p{
     width: 100px;
     height: 100px;
     background-color: blue;
   }
   div{
     width: 100px;
     height: 100px;
     background-color: red;
   }
    div,p{
      margin: 0;
      padding: 0;
    }
   </style>
</head>
<body>
  <div></div>
  <p></p>
</body>
</html>